Bug 1365278 - Remove WORD_CACHE_* telemetry probes that provide little value for their cost. r=milan

gfx/thebes/gfxFont.cpp

@@ -2604,13 +2604,8 @@ gfxFont::GetShapedWord(DrawTarget *aDrawTarget,
     }
     gfxShapedWord* sw = entry->mShapedWord.get();
 
-    bool isContent = !mStyle.systemFont;
-
     if (sw) {
         sw->ResetAge();
-        Telemetry::Accumulate((isContent ? Telemetry::WORD_CACHE_HITS_CONTENT :
-                                   Telemetry::WORD_CACHE_HITS_CHROME),
-                              aLength);
 #ifndef RELEASE_OR_BETA
         if (aTextPerf) {
             aTextPerf->current.wordCacheHit++;
@@ -2619,9 +2614,6 @@ gfxFont::GetShapedWord(DrawTarget *aDrawTarget,
         return sw;
     }
 
-    Telemetry::Accumulate((isContent ? Telemetry::WORD_CACHE_MISSES_CONTENT :
-                               Telemetry::WORD_CACHE_MISSES_CHROME),
-                          aLength);
 #ifndef RELEASE_OR_BETA
     if (aTextPerf) {
         aTextPerf->current.wordCacheMiss++;

toolkit/components/telemetry/Histograms.json

@@ -1650,38 +1650,6 @@
     "n_buckets": 20,
     "description": "Maximum retention time for the gradient cache. (ms)"
   },
-  "WORD_CACHE_HITS_CONTENT": {
-    "record_in_processes": ["main", "content"],
-    "expires_in_version": "never",
-    "kind": "exponential",
-    "high": 256,
-    "n_buckets": 30,
-    "description": "Word cache hits, content text (chars)"
-  },
-  "WORD_CACHE_HITS_CHROME": {
-    "record_in_processes": ["main", "content"],
-    "expires_in_version": "never",
-    "kind": "exponential",
-    "high": 256,
-    "n_buckets": 30,
-    "description": "Word cache hits, chrome text (chars)"
-  },
-  "WORD_CACHE_MISSES_CONTENT": {
-    "record_in_processes": ["main", "content"],
-    "expires_in_version": "never",
-    "kind": "exponential",
-    "high": 256,
-    "n_buckets": 30,
-    "description": "Word cache misses, content text (chars)"
-  },
-  "WORD_CACHE_MISSES_CHROME": {
-    "record_in_processes": ["main", "content"],
-    "expires_in_version": "never",
-    "kind": "exponential",
-    "high": 256,
-    "n_buckets": 30,
-    "description": "Word cache misses, chrome text (chars)"
-  },
   "FONT_CACHE_HIT": {
     "record_in_processes": ["main", "content"],
     "expires_in_version": "never",

toolkit/components/telemetry/histogram-whitelists.json

@@ -626,10 +626,6 @@
     "WEBCRYPTO_METHOD",
     "WEBCRYPTO_RESOLVED",
     "WEBSOCKETS_HANDSHAKE_TYPE",
-    "WORD_CACHE_HITS_CHROME",
-    "WORD_CACHE_HITS_CONTENT",
-    "WORD_CACHE_MISSES_CHROME",
-    "WORD_CACHE_MISSES_CONTENT",
     "XMLHTTPREQUEST_ASYNC_OR_SYNC",
     "XUL_CACHE_DISABLED"
   ],
@@ -1603,10 +1599,6 @@
     "WEBRTC_VIDEO_RECOVERY_AFTER_ERROR_PER_MIN",
     "WEBRTC_VIDEO_RECOVERY_BEFORE_ERROR_PER_MIN",
     "WEBSOCKETS_HANDSHAKE_TYPE",
-    "WORD_CACHE_HITS_CHROME",
-    "WORD_CACHE_HITS_CONTENT",
-    "WORD_CACHE_MISSES_CHROME",
-    "WORD_CACHE_MISSES_CONTENT",
     "XMLHTTPREQUEST_ASYNC_OR_SYNC",
     "XUL_CACHE_DISABLED"
   ],